1. Field of the Invention
The invention relates generally to determining a concentration of gas in space. More specifically, the invention relates to determining a concentration of oxygen in an space.
2. Description of the Related Art
The sensing of a gas, e.g., oxygen (O2), in a confined space is important in a number of applications. For instance, in automotive applications, oxygen sensors are critical to electronic fuel injection and emission control systems. In aircraft, oxygen sensors are needed to determine a concentration of oxygen in a fuel tank.
These oxygen sensors are most often implemented with a zirconia ceramic (“zirconia”) sensing element. The zirconia sensing element is often heated to temperatures around 700° F. The use of a zirconia sensing element heated to such a high temperature provides obvious hazards when implemented in a fuel tank, e.g., in an aircraft wing.
Furthermore, to increase safety of a fuel tank, an inerting system may be implemented. Some inerting systems operate by inserting an inert gas, such as nitrogen, into the fuel tank to bring the fuel to air ratio below the lower flammable limit. As such, it is beneficial to determine the concentration and/or amount of nitrogen and/or oxygen in the fuel tank.
Accordingly, it is desirable to provide a sensing system for measuring a concentration of oxygen in a confined space. It is also desirable to provide a sensing system for measuring a concentration of nitrogen (N7) in a confined space. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.